Project 4: Therapeutic Gene Editing for Rett Syndrome

项目 4：雷特综合征的治疗性基因编辑

• 批准号: 10668770
• 负责人: Cathleen M Lutz
• 金额: $ 46.97万
• 依托单位: JACKSON LABORATORY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-16 至 2028-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10668770
• 关键词: Adopted; Affect; Age; Age Years; Animals; Behavior Therapy; Biological Models; Birth; Breathing; Cell model; Cells; Characteristics; Clinical Trials; DNA Sequence Alteration; Deceleration; Disease; Disease Progression; Dose; Engineering; Event; Exons; FDA approved; Female; Fibroblasts; Gait abnormality; Genes; Grant; Growth; Hand; Head; Histologic; Human; In Vitro; Incidence; Language; Life Expectancy; Link; Measurement; Methods; Methyl-CpG-Binding Protein 2; Missense Mutation; Modeling; Movement; Mus; Mutation; Nature; Neonatal; Neurodevelopmental Disorder; Neurologic Deficit; Nonsense Mutation; Outcome; Patients; Pharmaceutical Preparations; Preparation; Proteins; Rett Syndrome; Safety; Seizures; Sleep disturbances; Speech; Stereotyping; Technology; Testing; Therapeutic; Titrations; Twin Multiple Birth; Variant; Viral; Work; X Chromosome; base; base editing; design; dosage; effectiveness testing; efficacy evaluation; efficacy study; genome editing; in vivo; male; mouse model; nervous system disorder; overexpression; pre-IND studies; pre-clinical; prime editing; pup; safety assessment; skills; small molecule; success; therapeutic gene; timeline; tool

PROJECT SUMMARY PROJECT 4 (Rett) Rett syndrome (RTT) is an X-linked neurodevelopmental disorder caused by mutations in the gene MECP2. The majority of RTT is caused by the same d eight reoccurring mutations in mutational hotspots of the 3rd and 4th exons. These four missense mutations and four nonsense mutations (R106W, R133C, T158M, R168X, R255X, R270X, R294X, and R306C) make up 70% of all Rett cases. RTT predominantly affects females, occurring at an incidence of 1-10,000 live female births and presents as a regression in milestones between the ages of 6-18 months. Hallmark characteristics of Rett include progressive loss of purposeful hand skills, speech and language regression, gait abnormalities, and stereotypic hand movements. Other features of the disorder include decelerated head growth, sleep disturbances, breathing abnormalities, and a high incidence of seizures. The life expectancy for patients with Rett is typically around 40-50 years of age. Landmark studies using conditional mouse models of Mecp2 to turn on the endogenous Mecp2 mouse gene post-symptomatically have convincingly demonstrated that neurological deficits associated with loss of Mecp2 is reversible to a significant degree. To date, clinical trials have focused on small molecules that modulate mechanisms downstream of MECP2. With more the 25+ such trials, limited success has been demonstrated with only modest behavior modifications and no approved FDA drugs for RTT. Gene and protein replacement strategies have been stymied with regards to controlled dosage affects that require precise titration of MECP2, as overexpression of Mecp2 in cells is toxic and are further confounded by the X-linked nature of the disease with cell to cell variation of MECP2 expression resulting from chromosome X-linked inactivation. For these reasons, base editing strategies that directly correct the endogenous genetic mutation and restore MECP2 to endogenous cellular levels are an extremely attractive therapeutic strategy for RTT. In this follower project, we aim to correct missense and nonsense mutations to enable rescue of disease progression in Rett patients. Specifically, we aim to: (1) Design, test and optimize Base Editing, Prime editing and Twin Editing strategies for 5 different mutations; (2) Test these strategies in mouse models containing humanized exons with engineered missense and nonsense mutations. (3) Perform pre-clinical IND enabling studies to assess safety and efficacy. We will work closely with the Gene Editing Core to develop the latest base editing and/or prime editing technologies in RTT model systems. We will iterate with the Gene Editing Core to ensure that our genome editing tools maximize on-target editing efficiencies, minimize undesirable gene editing byproducts and off-target editing events, and maximize compatibility with in vivo delivery methods of potential therapeutic relevance.

项目摘要项目 4 (Rett) Rett 综合征 (RTT) 是一种由 MECP2 基因突变引起的 X 连锁神经发育障碍。 大多数 RTT 是由第三和第三个突变热点中相同的 d 八个重复发生的突变引起的 第四外显子。这四种错义突变和四种无义突变（R106W、R133C、T158M、R168X、 R255X、R270X、R294X 和 R306C）占所有 Rett 案例的 70%。 RTT 主要影响女性， 发生率是 1-10,000 名活产女性，并呈现为 6-18 个月的年龄。雷特的标志性特征包括逐渐丧失有目的的手部技能、言语 以及语言退化、步态异常和刻板的手部动作。该疾病的其他特征 包括头部生长减慢、睡眠障碍、呼吸异常和癫痫发作率高。 Rett 患者的预期寿命通常为 40-50 岁左右。具有里程碑意义的研究使用 Mecp2 条件小鼠模型在症状后开启内源性 Mecp2 小鼠基因 令人信服地证明，与 Mecp2 缺失相关的神经功能缺陷是可逆的 程度。迄今为止，临床试验主要集中在调节下游机制的小分子。 MECP2。经过超过 25 次此类试验，仅通过适度的行为取得了有限的成功 修改，且 FDA 尚未批准 RTT 药物。基因和蛋白质替代策略受到阻碍 关于需要精确滴定 MECP2 的受控剂量影响，因为 Mecp2 在 细胞是有毒的，并且该疾病的 X 连锁性质与 MECP2 的细胞间变异进一步混淆 X连锁染色体失活导致的表达。由于这些原因，碱基编辑策略 直接纠正内源性基因突变并将MECP2恢复到内源性细胞水平是一种 RTT 极具吸引力的治疗策略。 在这个追随者项目中，我们的目标是纠正错义和无义突变，以拯救疾病 Rett 患者的进展。具体来说，我们的目标是：（1）设计、测试和优化Base Editing、Prime Editing 以及针对 5 种不同突变的双胞胎编辑策略； (2) 在含有以下成分的小鼠模型中测试这些策略 具有工程错义和无义突变的人源化外显子。 (3) 进行临床前IND启用 评估安全性和有效性的研究。我们将与基因编辑核心紧密合作，开发最新的基地 RTT 模型系统中的编辑和/或主编辑技术。我们将迭代基因编辑核心 确保我们的基因组编辑工具最大限度地提高靶向编辑效率，最大限度地减少不良基因编辑 副产物和脱靶编辑事件，并最大限度地提高与潜在体内传递方法的兼容性 治疗相关性。